Provided is a spindle motor comprising a stator and a shaft provided in the stator. A rotor is coupled with the shaft, and a turntable is connected with the shaft. The turntable has a ball container for receiving a plurality of ball, and the ball container has an inclined inner or outer wall. A ball cover is coupled with the ball container and having decelerating means. Herein, the decelerating means comprise an inclination or protrusions formed in the ball cover.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A spindle motor comprising: a stator; a shaft provided on the stator; a rotor coupled with the shaft; a turntable connected with the shaft, and having a ball container for receiving a plurality of balls therein, the ball container having an opening; and a ball cover configured to close the opening, wherein a decelerating portion is provided at the ball cover, for increasing a frictional force applied to the balls, when the turntable decelerates, and wherein the decelerating portion comprises an inclination of the ball cover, the inclination having a downwardly inclined portion declining away from the shaft in a radial direction of the shaft and having a downwardly inclined length that is shorter than a diameter of a corresponding ball such that the deceleration portion engages a circumference of the balls to decelerate the balls.
2. The spindle motor according to claim 1 , wherein the inclination is rounded.
3. The spindle motor according to claim 2 , wherein the inclination is rounded circumferentially at a curvature the same as that of the balls.
4. The spindle motor according to claim 1 , wherein the inclination of the ball cover has a height of about 0.05 to 0.1mm.
5. The spindle motor according to claim 1 , wherein the inclined surface is a single inclined surface in the ball container.
6. The spindle motor according to claim 1 , wherein the ball container further comprises an inclined side wall for raising the balls to an upward position along the side wall when the turntable rotates, and the downwardly inclined portion engages the outer circumference of the balls when the turntable stops its rotation and the balls move down from the upward position to a bottom of the ball container such that the balls contact the inclined side wall and the inclined portion and decelerate.
7. The spindle motor according to claim 6 , wherein the downwardly inclined portion engages the outer circumference of the balls at a position that is behind a vertical center axis of the corresponding ball such that the corresponding ball is inclined toward the inclined side wall.
8. The spindle motor according to claim 1 , wherein the ball cover is formed over the rotor and the ball cover is separated from the rotor.
9. A spindle motor comprising: a stator having a base plate, a bearing housing provided on the base plate, a core assembly provided on the bearing housing; a shaft coupled with a metal bearing mounted on the bearing housing; a rotor coupled with the shaft, and having a cylindrical rotor yoke and a magnet provided on the rotor yoke in a position opposed to the core assembly; a turntable connected with the shaft, and having a ball container for receiving a plurality of balls therein, the ball container having an opening; and a ball cover configured to close the opening, wherein the ball container has an inner wall, an upper wall corresponding to the opening and an outer wall, and the outer wall is inclined to guide an up and down movement of the balls, wherein the ball cover has an decelerating portion formed at a contact position of the balls, when the ball moves downward along the outer wall, and wherein the decelerating portion comprises protrusions, provided on the ball cover and separated from the inner wall and the outer wall of the ball container, and portions of the ball cover between the inner wall and one edge of the protrusions and between the outer wall and another edge of the protrusions are planar.
10. The spindle motor according to claim 9 , wherein the protrusions are provided in the number of more than 3.
11. The spindle motor according to claim 9 , wherein the protrusions have a height of about 0.05 to 0.1mm.
12. The spindle motor according to claim 11 , further comprising a buffer member for buffering impact at the mounting of an optical disk and preventing slippage.
13. The spindle motor according to claim 9 , wherein the ball cover is formed over the rotor and the ball cover is separated from the rotor.
14. A spindle motor comprising: a stator; a shaft provided on the stator; a rotor coupled with the shaft; a turntable connected with the shaft, and having a ball container for receiving a plurality of ball therein, the ball container having an opening; and a ball cover configured to close the opening and including a first plane surface, a second plane surface and an inclined surface in a circumferential direction, wherein the inclined surface is formed between the first plane surface and the second plane surface, and wherein the inclined surface includes a downwardly inclined portion declining away from the shaft in a radial direction of the shaft and having an downwardly inclined length that is shorter than a diameter of a corresponding ball such that the deceleration portion engages a circumference of the balls to decelerate the balls.
15. The spindle motor according to claim 14 , wherein the inclined surface is a single inclined surface in the ball container.
16. The spindle motor according to claim 14 , wherein the ball container further comprises an inclined side wall for raising the balls to an upward position along the side wall when the turntable rotates, and the downwardly inclined portion engages the outer circumference of the balls when the turntable stops its rotation and the balls move down from the upward position to a bottom of the ball container such that the balls contact the inclined side wall and the inclined portion and decelerate.
17. The spindle motor according to claim 16 , wherein the downwardly inclined portion engages the outer circumference of the balls at a position that is behind a vertical center axis of the corresponding ball such that the corresponding ball is inclined toward the inclined side wall.
18. The spindle motor according to claim 14 , wherein the ball cover is formed over the rotor and the ball cover is separated from the rotor.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
May 12, 2004
October 7, 2008
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